Fixed picker.js throwing random requirejs script error on development

In Community (development), this script error is rather constant than random: 

![screenshot 2014-12-30 15 01 18](https://cloud.githubusercontent.com/assets/1451471/5579688/0bea0b76-903f-11e4-9982-35bdce59f7ef.png)

Putting `picker` components in `requirejs` config seems to fix the issue. Console is clean :clap: